Method for producing lead compounds



Dec.` 29 1925.

B. MEAD METHOD FOR PRODUCING LEAD COMPOUNDS Filed June 14, 1925 E W E Q m U D fj n l H HU/ HD a w! v nl@ v wmv?. W .u u. .u 1 \W Patented Dec. 29, 1925.

UNITED STATES 1,567,159` PATENTA FFICE.

'BRIAN MEAD, or BosToN, MASSACHUSETTS, AssIeNon, BY Milam:v AssIemNTs, To GENERAL morons connonATIoN, or DETROIT, moment, A conPonATIoN or DELAWARE.

unTHoD ron. rnoDUcxNe LEAD ooltvrounns.

Application :ned :une u, 192s. semi x6. uam.

To all lwhom t may concer/vt.' 5

Be it known that I, BaIANMn'AD, a subject of the King of Great Britain, residing at 61 Mountort Street, Boston,-.Massachu- 5 set-ts, have invented certain new and useful Improvements in Methods :t'or- Producing Lead Compounds, of which the following is a full, clear, and exact description. l This invention relates to modes of producing lead tetra alkyls, and, moreV articularly, lead tetraethyl, and its principa objects are to promote an intimate relation between the v substances employed Aand to electrically re ducethe reaction mass. In the accompanying drawings: Fig. 1 is a plan View of an apparatus adapted to carry out my process; and Flg. 2is a sectional view thereof, taken substantiall on the line 2-2of Fig. 1.

vIn these diiawings is a'tank containing a porous cup 11 made of clay or other material, which divides the interior of the tank into an inner chamber- 12 within the cup and an outer chamber 13 between the cup and the tank walls. A series of graphite anodes 14, (shown herein as six in number) are held in Vertical positions in the outer chamber 13 by a tank cover 15 through which the anodes project. The outer ends of the anodes are connected in an electrical circuit by a wire 16.

The porous cup 11 has a cover 17 of nonconductinns material, for example, hard rubber, sealed along` its periphery by asphalt 18.

Metal ferrules' 19 with rubber attachment seated in vthe cover 17 support leads 20 which are attached at their inner endsl to an annular lead cathode 21 and at their outer ends to a wire 22 connected in the electrical circuit with wire 16. 23 is avthermometer, and 24 la reflux condenser having a condensing chamber 25 communicating with the inside of cup 11, and a cooling chamber 26 having connections for circulating a lcooling medium about the condensing chamber 25. Mounted on the cover 17 is a mercury seal 27 for an agitator comprising a rod 28 projecting through the seal, gears 29 connecting the outer end 'of the rod with a power` shaft 30 and propeller blades 31 onthe inner end ofthero.` u

The cell is placed on a hot plate 32 or similar means' for controlling the temperature of the electrolyte.

The chamber 12 within the cup is partially filled with aA catholyte comprising by weight 90 parts of water 10 parts of NaOH, 10A

parts of ethyl iodi e, and 1 part casein, and the chamber 13 around the cup is partially Iilled'with an anolyte comprisin l10 parts N aOH in 90 parts of water. T e1ectro lyte is heated to about 55 C., or just below the boiling point of the ethyl iodide, the agitator is started, and the current is turned on, a current density of about 1.15 ampere per dm2 being preferred. The reflux apparatus condenses and returns to the cup the ethyl iodide which vaporizes during the reaction. The stirring roduces an emulsion of casein and ethyl 1 ide in the water and thisemulsion promotes homogeneity of the mixture and an intimate contact between the ingredients of the cell and, more articularly, between the ethyl iodide and t e lead. Apparently the hydrogen formed at the cathode reduces the reaction mass, forming vlead diethyl which is unstable at the temperature used and breaks up thermally into lead and lead tetraeth l. T he lead tends to settle tothe bottom o the cup.

When the reaction is completed, the NaOH is decanted ott and the heavier lead tetraethyl is steam distilled out and collected in another vessel.

The composition of the reaction mass may be varied by using in place of the ethyl iodide, other alkyl hahdes, for example, methyl iodide, amyl iodide, and methyl, amyl, and ethyl 'bromides Slight alkalinity of the electrolyte prometes the reaction and avoids acidity which is detrimental to the reaction. I claim: 1. The process of producing a lead alkyl which comprises forming an emulsion of an alkyl halide in water, placing lead in contact with the emulsion, and reducing the reaction mass thus formed.

2. A process as set forth in claim 1 in which the temperature of the reaction mass is maintained slightly below the boiling point of the alkyl halide.

3. A rocess as set forth in claim 1 in which t e alkyl halide is an ethyl halide and lead tetraethyl is formed.

4. A rocess as set forth in claim 1 in whichtiie alkyl halide is an alkyl iodide.

5. A process as set forth in c aim 1 1n 'which the alkyl halide is ethyl iodide and lead tetraethyl is formed.

6. The process of producin a lead alkyl which comprises forming an' e ectrolytc comprisi'ng an emulsion of an alkyl halide, and reducing the electrolyte by an electric current through lead in contactl with the electrolyte.

7. A process as set forth m claim 6 1n which the emulsion isv formed in an alkaline solution.

which the emulsion is formed with casein.

9. The process of producing a lead alkyl which comprises forming an electrolyte comprising an emulsion of an alkyl halide 1n an lalkaline Water solution, and reducing the electrolyte by an electric current through a lead cathode.

10, A process as set forth in claim 9 in which the temperature of the reaction mass is maintained slight] below the boiling pcintof the alkyl hali e.

11. vA process as set -forth in claim 9 in which thevalkyl halide i's an ethyl halide and lead tetraethyl is formed.

12. A process as sei', forth in claim 9 in which the alkyl halide is an alkyl iodide.

13. A process as set, forth in claim 9 in v which the alkyl `halide is ethyl iodide and 8. A process as set forth 1n clalm 6 in lead tetraethyl is formed.

14. A process as set forth in claim 9 in which an emulsion of an alkyl halide and casein is formed in an alkaline water solution.

In testimony whereof l hereto ax my signature.

BRlAN MEAD. 

